Corona generator cleaning apparatus

ABSTRACT

An improved apparatus is provided for cleaning the discharge electrode or electrodes of a corona generating device. The apparatus includes a cleaning element which is adapted to traverse the operative length of the electrode. An edge of the cleaning element engages the electrode to provide an effective scraping action on the surface thereof to clean the debris such as dust particles and toner particles therefrom. Preferably, the element cocks in operation to provide a first edge for scraping the electrode when the element is traversed in a first direction and a second edge for scraping the electrode when the element is traversed in an opposing direction. Preferably, the cleaning element also includes means for cleaning the shield of the corona generator. An electrostatographic reproducing apparatus incorporating the aforenoted cleaning apparatus also forms part of the instant invention.

United States Patent [191 Van Buskirlr CORONA GENERATOR CLEANINGAPPARATUS Inventor: Warren T. Van Buskirk, Rochester,

[73] Assignee: Xerox Corporation, Stamford,

, Conn. 22' Filed: July 18, 1973 [21] Appl. No.: 380,302

[52] US. Cl. 250/324, 317/262 A [51] Int. Cl. H0lj 37/26 [58] Field ofSearch 250/324, 325, 326; 317/262 A [56 References Cited UNITED STATESPATENTS 2,614,901 10/1952 Jacob 346/35 2,725,304 11/1955 Landrigan117/17.5 2,811,135 10/1957 Hayford et a1... 250/324 3,339,069 8/1967Hayne et al 250/326 3,471,695 10/1969- Hudson et aL... 250/324 3,496,3522/1970 .lugle 250/326 3,499,143 3/1970 Martin 250/324 Oct. 15, 1974Primary Examiner-James W. Lawrence Assistant Examiner-B. C. AndersonAttorney, Agent, or Firm-James .l. Ralabat e; Clarence A. Green; PaulWeinstein [57 1 ABSTRACT An improved apparatus is provided for cleaningthe discharge electrode or electrodes of a corona generating device. Theapparatus includes a cleaning element which is adapted to traverse theoperative length of the electrode. An edge of the cleaning elementengages the electrode to provide an effective scraping action on thesurface thereof to clean the debris such as dust particles and tonerparticles therefrom. Preferably, the element cocks in operation toprovide a first edge for scraping the electrode when the element istraversed in a first direction and a second edge for scraping theelectrode when the element is traversed in an opposing direction.Preferably, the cleaning element also includes means for cleaning theshield of the corona generator. An electrostatographic reproducingapparatus incorporating the aforenoted cleaning apparatus also formspart of the instant invention.

28 Claims, 8 Drawing Figures PAIENIEBBEI x 51914 SHEET 1 0F 4 BACKGROUNDOF THE INVENTION This invention relates to a corona generator cleaningapparatus and to an electrostatographic reproducing machineincorporating the cleaning apparatus.

Corona generating devices are employed for a variety of purposes inelectrostatographic reproducing machines including, for example,charging of the electrostatic imaging plate; electrostatic transfer of adeveloped image to an image receiving member; removal of backgroundtoner particles from a developed electrostatic latent image; andcleaning of the electrostatic imaging plate by neutralizing the chargeon residual toner particles. I

One particularly useful type of cornoa generating device is described indetail in U.S. Pat. No. 2,836,725 issued to Vyverberg. This device isusually comprised of at least one corona discharge electrode or coronodewire which is partially surrounded by a conductive shield.

Although this corona generating device is adapted to provide a uniformelectrostatic charge on the desired surface, dust particles, tonerparticles, or other debris accummulating on or about the coronode wireand shield can cause non-uniform generation of corona current along thelength of the coronode wire and may reduce the magnitude of the coronacurrent generated.

Avariety of techniques have been devised to reduce or remove suchcontamination such as those set forth in U.S. Pat. Nos. 3,324,291,3,339,069, 3,382,360, 2,471,965, 3,483,372, 3,496,352 and 3,499,143. Oneparticularly useful approach for cleaning the electrodes has been towipe the electrodes so as to remove dust and toner particlecontamination. Examples of this approach are set forth in U.S. Pat. Nos.2,614,901, 2,81 1,135 and IBM Technical Disclosure Bulletin, Vol. 8, No.8, Jan. 1969, by Voit, Jr.

It is particularly desirable for a charging corona generator to deposita uniform layer of electrostatic charges on the surface of theelectrostatic imaging plate in order to provide high quality images.Contaminated coronode wires provide non-uniform corona generation alongtheir length and, therefore, non-uniform charge deposition on theimaging plate.

Thecreation of a corona current is predominately determined 'by thepotential difference between the coronode wire and the shield. Dustparticles and toner particles which accumulate on the inner walls of theshield produce deleterious effects, particularly for a grounded metalshield. These particles are comprised of dielectric material which canstore the charged ions communicated thereto from the coronode wire. Asthe charge builds up on these particles, a voltage is provided on thecontaminated portion of the inner wall of the surrounding shieldresulting in a non-uniform potential difference between the coronodewire and the shield with consequentvariations in corona discharge alongthe length of the corona generator. This latter problem is particularlyassociated with corona generating devices employing a metallic shield.For corona generating devices employing a dielectric shield constructed,for example, of a plastic material such as Teflon or Mylar theaccumulation of such particles on the shield has no appreciable effecton the corona generated current uniformity.

SUMMARY OF THE INVENTION In accordance with this invention an improvedapparatus is provided for cleaning the discharge electrode of a coronagenerating device. Contrary to the approaches of the prior art inaccordance with this invention the cleaning is accomplished by scrapingthe discharge electrodes. The apparatus in accordance with thisinvention includes a cleaning element which is adapted to traverse theoperative length of the electrode. An edge of this cleaning elementengages the electrode to provide an effective scraping action on thesurface of the electrode to clean debris such as dust particles andtoner particles therefrom.

Preferably the element cocks in operation to provide a first edge forscraping the electrode when the element is traversed in a firstdirection and a second edge for scraping the electrode when the elementis traversed in an opposing direction. Preferably the cleaning elementalso includes means for cleaning the shield of the corona generator.

The discharge electrode preferably comprises a coronode wire. Due to thecocking action of the cleaning element the coronode wire is normallydeflected so that it is biased into contact with the scraping edge ofthe cleaning element. Therefore, the cleaning element preferably isdisengaged from the wire in the home position to allow the wire toassume its proper undeflected position.

It is also preferred in accordance with this invention to provide aspring biased return means for returning the cleaning element to thehome position. An electrostatographic reproducing apparatusincorporating the aforenoted cleaning apparatus also forms a part of theinstant invention.

Accordingly, it is an object of this invention to provide an apparatusfor cleaning the discharge electrode or electrodes of a coronagenerating device.

It is a further object of this invention to provide an apparatus asabove which is effective to remove contaminants from dischargeelectrodes by a scraping action.

It is a further object of this invention to provide an apparatus asabove further including means for cleaning the shield associated withthe corona generating device.

It is a still further object of this invention to provide anelectrostatographic reproducing machine incorporating the aforenotedcorona generator cleaning apparatus.

These and other objects will become more apparent from the followingdrawings and description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows schematically anelectrostatographic reproducing'machine in accordance with thisinvention.

. FIG. 2 is a perspective view of a corona generator cleaning apparatusin accordance with this invention.

FIG. 3 is a partial cross-sectional view of the cleaning I FIG. 5 is apartial cross-sectional view of the cleaning apparatus of this inventiontraversing in an opposing direction.

FIG. 6 is a perspective view of an alternative embodiment of a cleaningapparatus in accordance with this invention.

FIG. 7 is a bottom view of the device of FIG. 6 showing the cockingaction.

FIG. 8 is a front view of a cleaning member in accordance with apreferred embodiment of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG.1 there is shown by way of example an electrostatographic reproducingmachine 1 which incorporates the improved corona generator cleaningapparatus 2 of the present invention. The reproducing machine 1 depictedin FIG. 1 illustrates the various components utilized therein forxerographically producing copies from an original. Although the cleaningapparatus of the present invention is particularly well adapted for usein an automatic xe rographic reproducing machine 1 it should becomeevident from the following description that it is equally well suitedfor use in a wide variety of electrostatographic systems and isnotnecessarily limited in its application to the particular embodimentshown herein.

The reproducing machine illustrated in FIG. 1 employs an image recordingdrum-like member 10, the outer periphery of which is coated with asuitable photoconductive material 11. One type of suitablephotoconductive material is disclosed in U.S. Pat. No. 2,970,906, issuedto Bixby in 1961. The drum 10 is suitably journaled for rotation withina machine frame (not shown) by means of a shaft 12 and rotates in thedirection indicated by arrow 13, to bring the image retaining surfacethereon past a plurality of xerographic processing stations. Suitabledrive means (not shown) are provided to power and coordinate the motionof the various cooperating machine components whereby a faithfulreproduction of the original input scene information is recorded upon asheet 14 of final support material such as paper or the like. Thepractice of xerography is well-known in the art, and is the subject ofnumerous patents and texts, including Electrophotography by Schaffert,published in 1965, and Xerography and Related Processes, by Dessauer andClark, published in 1965. The various processing stations for producinga copy of an original are herein represented in FIG. 1 as blocks A to E.Initially the drum 10 moves photoconductive surface 11 through chargingstation A. In charging station A an electrostatic charge is placeduniformly over the photoconductive surface 11 of the drum 10 preparatoryto imaging. The charging may be provided by corona generating device ofa type described in U.S. Pat. No. 2,836,725, issued to Vyverberg in1958.

Thereafter, the drum 10 is rotated to exposure station B where thecharged photoconductive surface 11 is exposed to a light image of theoriginal input scene information, whereby the charge is selectivelydissipated in the light exposed regions to record the original inputscene in the form of a latent electrostatic image. A suitable exposuresystem may be of the type described in U.S. Pat. application, Ser, No.259,181, filed June 2, 1972, or U.S. Pat. No. 3,330,181 issued toJakobson in 1967. After exposure, drum 10 rotates the electrostaticlatent image recorded on the photoconductive surface 11 to developmentstation C wherein a conventional developer mix is applied to thephotoconductive surface 11 of the drum l0 rendering the latent imagevisible. A suitable development station is disclosed in U.S. Pat. No.3,707,947 issued to Reichart in 1973. The patent describes a magneticbrush development system utilizing a magnitizable developer mix havingcarrier granules and a toner colorent. The developer mix is continuouslybrought through a directional flux field to form a brush thereof. Theelectrostatic latent image recorded on photoconductive surface 11 isdeveloped by bringing the brush of developer mix into contact therewith.

The developed image on the photoconductive surface 11 is then broughtinto contact with a sheet 14 of final support material within a transferstation D and the toner image is transferred from the photoconductivesurace 11 to the contacting side of the final support sheet 14. Thefinal support material may be paper, plastic, etc., as desired. Afterthe toner image has been transferred to the sheet of final supportmaterial 14 the sheet with the image thereon is advanced to a suitablefuser 15 which coalesces the transferred powder image theretojOne typeof suitable fuser is described in- U.S. Pat. No. 2,701,765, issued toCodichini, et al. in 1955. After the fusing process the sheet 14 isadvanced by rolls 16 to catch tray 17 for subsequent removal therefromby the machine operator.

Although a preponderance of the toner powder is transferred to the finalsupport material 14, invariably some residual toner remains on thephotoconductive surface 11 after the transfer of toner powder image tothe final support material 14. The residual toner particles remaining onthe photoconductive surface 11 after the transfer operation are removedfrom the drum 10 as it moves through cleaning station E. Here theresidual toner particles are first brought under the influence of acleaning corona generating device 18 adapted to neutralize theelectrostatic charge remaining on the toner particles. The neutralizedtoner particles are then mechanically cleaned from the photoconductivesurface 11 by conventional means as, for example, the use of aresiliently biased knife blade asset forth in U.S. Pat. No. 3,660,863,issued to Gerbasi in 1972. It is preferred in accordance with thisinvention that the sheets of final support material 14 processed in theautomatic xerographic reproducing machine will be stored in the machinewithin a removable paper cassette 19. A suitable paper cassette as setforth in U.S. Pat. application, Ser. No. 208,138 field Dec. 15, 1971.

The copier in accordance with this invention can also have thecapability of accepting and processing copying sheets of varyinglengths. The length of the copy sheet, of course, being dictated by thesize of the original input scene information, recorded on thephotoconductive surface 11. To this end the paper cassette 19 ispreferably provided with an adjustable feature whereby sheets of varyinglength and width can be conveniently accommodated therein. In operationthe cassette 19 is filled with a stack of final support material ofpreselected size and the cassette 19 is inserted into the machine inoperable relationship with a pair of feed rolls 20. When properlypositioned in communication with the feed rolls 20 the top most sheet 21of the stack is separated and forwarded from the stack into the transferstation D by means of registration rolls 22.

It is believed that the foregoing description is sufficient for purposesof the present application to illustrate the general operation of anautomatic xerographic copier l which can embody the teachings of thepresent invention.

Referring now to FIG. 2 there is shown by way of example a specificembodiment of a corona generator cleaning apparatus 2 in accordance withthis invention. The corona generator shown in FIG. 2 comprises thecharging corona generator A of the apparatus 1 of FIG. 1. Thegenerator30 comprises a partially surrounding shield 31 and a coronode wire 32.The coronode wire 32 acts as a corona discharge electrode. While onlyone discharge electrode is shown, the corona generator may have anydesired number of electrodes. The shield 31 is formed of metal and isconnected to ground potential. The coronode wire 32 is connected to asuitable source ofhigh voltage (not shown) by means of wire 33. The wire32 in the embodiment shown is stationary and is supported at both of itsends by means of clamps 34. The wire 32 is held taut between the clamps34 so that it is uniformly positioned at a proper distance from thephotoconductive surface 11.,As previously noted, the environment in anelectrostatographic reproducing machine is not sufficiently clean tomaintain the shield 31 and coronode wire 32 free from contamination bydust particles, toner particles or other debris. In the embodimentshown, a slot 35 is provided in the back portion 36 of the shield 31 toprovide for communication with a cleaning means 37. The cleaning means37 is positioned within the shield 31 and about the coronode wire 32 sothat it can be traversed along the operative length of the wire andshield. The cleaning means is operative to clean the coronode wire 32and preferably also the shield 31.

The cleaning means 37 in accordance with this invention comprises amovable member 38 or cleaning element having a body portion 39 with aslot 40 therein so that the element may be fit about the coronode wire32. Two legs 41 project outwardly from the body portion 39 in parallelalignment on either side of the slot 40. A carriage member 42 having aslot 43 therein adapted to pivotably receive the legs 41 of the element38 is provided which is adapted to shuttle back and forth in substantialaxial alignment with the coronode wire 32. The legs 41 of the cleaningelement 38 are preferably pivotably secured within the slot 43 of thecarriage member 42 by means of pin 44 so that the cleaning element maycockin one or the other directions of travel. The legs 41 of thecleaning element 38 protrude through the slot 35 in the back of theshield 31. The slot 35 is in axial alignment with the wire 32 and isoperative to guide the cleaning element 38 along the wire.

The cleaning element 38 is driven to and fro along the wire 32 by meansof a cable drive 50. In the embodiment shown, the cable drive comprisesa first cable portion 51 connected between a first tab 52 of thecarriage member 42 and an automatic return means 53 via pulley 54. Thereturn means 53 preferably comprises a spring loaded rewind mechanism ofconventional design. A. second cable portion 55 is provided which isconnected via pulley 56 between a second tab 57 of the carriage member42 and a means 58 for actuating the cleaning means 37. The actuationmeans 58 shown in FIG. 2 comprises a knob which permits the operator tomanually pull on the cable 55 to thereby cause the cleaning means 37 totraverse the wire 32 and shield 31 in a first direction over theoperative lengths thereof. Upon releasing the knob 58 the cleaning means37 is caused to traverse the wire 32 and shield 31 in the opposingdirection automatically by operation of the spring biased rewindmechanism 53. The length of the slot 35 governs the distance over whichthe cleaning means 37 may be traversed. The length which is employed isat least as great and preferably greater than the operative length ofthe wire 32 and shield 31. Operative length of the wire 32 and shield31, as the term is used herein, refers to that portion of the length ofthe wire and shield which is operative to charge the desired surfacesuch as photoconductive surface 11.

The cleaning element 38 shown in FIG. 2 includes a means 60 for cleaningthe inside portion 61 of the shield 31. The cleaning means 60 preferablycomprises brushes formed of any desired material and having any desiredstructure such as, for example, fiberous or foam-like. One particularlyuseful material is sold under the trademark Velcro by the l-IeartwellCorporation, 9035 Dennis Boulevard, Los Angeles, Calif. This materialconsists of loop-type fibers 62 as better shown in FIG. 8, which areformed of a material such as nylon. This type of brush 60 has proved tobe highly effective since the fibers 62 have increased stiffness byvirture of their looped nature.

The shield 31 as shown in FIG. 2 has a structure designed to provideimproved strength in consideration of the slot 35 which is provided init. The shield 31 preferably comprises a member of rectalinearcross-section having a channel defined by surface 61 of substantiallyhemospherical cross-section formed therein.

Referring now additionally to FIGS. 3 through 5, the operation of thecleaning apparatus 2 in accordance with this invention will be moreclearly set forth. FIG. 3 shows the cleaning apparatus 2 in the homeposition H. The home position as the term is employed in accordance withthis invention, comprises the starting position or rest position for thecleaning element 38 when it is not actuated. The home position of theshield 32 is provided with ramps which contact the shoulders 71 (FIG. 8)of the cleaning element 38 to force the element out of engagement withthe coronode wire 32. It is desirable to maintain the distance betweenthe wire 32 and the photoreceptive surface 11 substantially constantalong the length of the wire, and, therefore, when the cleaningapparatus 2 is not in use it should be disengaged from the wire so as toavoid any deflection thereof.

Upon pulling the knob 58 in FIG. 2, and the cable 55 associatedtherewith out from the machine, the carriage 42 and cleaning element 58are caused to traverse the coronode wire 32 in a first direction asshown by arrow in FIG. 4 toward the end of travel position 73 of theslot 35. Since the cleaning element 38 is pivoted in the carriage 42, itcocks away from the direction of travel during traverse so that at leastone first edge 81 of the cleaning element is caused to engage the wire32 and scrape its surface clean of any contaminants. The engagementprovided in accordance with this invention is unique as compared to theprior art devices in that an edge of the cleaning member is caused toscrape rather than just wipe the wire to remove contaminants.

Scraping is highly effective for cleaning the wire 32.

Therefore, in the broadened sense in accordance with this inventionthere is provided an effective cleaning apparatus 2 which comprises anelement 38 having at least one edge 81 which is operative to scrape thewire 32 to remove contaminants therefrom.

The cleaning element 38 traverses the wire 32 until it reaches its endof travel position 73 which is near the end of the wire 32 and outsidethe operable zone of the wire. At this time the knob 58 is released andthe cleaning element is caused to traverse the wire 32 in the opposingdirection as shown by arrow 82 in FIG. 5 back towards the home positionH under the action of the spring rewind mechanism 53. Upon changingdirections the cleaning element 38 cocks longitudinally away from thedirection of travel so that at least one second edge 83 is caused toengage the wire 32.

This is a particulary effective cleaning apparatus since one edge 81 ofthe cleaning element 38 scrapes the wire 32 during the initial traversefrom the home position H to the end of travel position 73 and adifferent edge 83 is caused to scrape the wire during the returntraverse to the home position. Therefore, any particles or contaminantsaccumulated on the first edge 81 during the initial traverse do notinterfere with the further cleaning during the return traverse.

It is preferred in accordance with this invention in order to achievethe optimum cleaning action that the cleaning element 38 engage the wire32 so as to deflect it and thereby be biased against it during thecleaning operation as shown in FIGS. 4 and 5.

Preferably the slot 40 width is selected to provide the best scrapingaction for the largest portion of the cir' cumference of the wire 32.Therefore, the slot 40 size is selected such that the width of the slotis about the same as the diameter of the wire 32. Preferably the widthof the slot is within about +0.000 inch and 0.005 inch of the diameterof the wire 32. The bottom of the slot 40 as shown in FIG. 8 preferablyconforms to the shape of the wire 32 which in the embodiment shown iscircular.

The rest position of the wire is shown as the dashed line ,R in FIGS. 4and 5. The amount of deflection shown is exaggerated for purposes ofillustration. The actual deflection of the wire would generally be lessthan about 0.060 inch and preferably less than about 0.025 inch.

While is is preferred to have the slot 40 width conform as closely aspossible to the diameter of the wire 32, the slot width may be set asdesired. The preferred slot 40 width provides for the optimum cleaningaction for the greatest portion of the circumference of the wire. Forsome applications, however, it may be desirable to employ a larger slot40 width and thereby only scrape clean that portion of the wire 32 whichfaces the surface being charged. The edges 81 and 83 are effective toclean this latter surface irrespective of the slot 40 width. This latterapproach also would provide less wear on the wire due to cleaning. Thepreferred approach, however, provides the best cleaning, and, therefore,the most uniform charge distribution from the cleaned wire.

The shield cleaning means 60 is effective to wipe the shield 31 cleanduring both the initial traverse and the return traverse of the cleaningelement 38.

Referring now to FIGS. 6 and 7 there is shown an alternative embodimentof this invention wherein the carriage 42' is connected to the cables 51and 55 at points 52' and 57 spaced apart transverse to the direction oftravel and the wire 32 axis such that the cleaning element 38 is causedto be cocked transverse to the direction of travel and the wire axis.This cocking action may be provided in place of the previously describedaction with reference to FIGS. 4 and 5 by rigidly mounting the cleaningelement 38 to the carriage 42' or alternatively a combination of cockingactions both in the transverse and longitudinal directions withreference to the wire 32 axis and the direction of travel may beprovided by allowing the cleaning element 38 to pivot in the carriage 42as shown. The carriage 42' includes the slot 43' which is adapted toreceive the legs 41 of the cleaning element 38. The legs 41 arepivotably secured within the slot 43' by means of the pin 44'. Thecorona generator 30 shown in FIG. 6 is a partial view of the one shownin FIG. 2 and the means 58 for actuating the cleaning means 37 and themeans 53 for returning the cleaning means to its home position would bearranged substantially as set forth in FIG. 2.

Referring specifically to FIG. 7 the transverse cocking action of thecleaning element 38 of FIG. 6 is illustrated. By cocking the cleaningelement 38 transverse to the axis of the wire 32 at least a first pairof edges and 91 are caused to scrapingly engage the wire during itsinitial traverse. During its return traverse at least a second pair ofedges 92 and 93 are urged into scraping engagement'with the wire 32. Asshown, the wire 32 is deflected laterally in different directions on theopposing sides 94 and 95 of the cleaning element 38. It should berecognized that this type of transverse cocking action would provide aneffective cleaning action by providing more than one edge 90 and 91 or92 and 93 to scrapingly engage the wire 32.

The combination of transverse and longitudinal cocking action wouldprovide an improved cleaning action by virtue of the increasedcircumferential area of the wire 32 which would be scraped by theelement 38. As with the previously discussed embodiment the cleaningmeans 37 also includes brushes 60 adapted to clean the shield 31. Theadvantages previously noted with respect to providing a first edge oredges for cleaning during the initial traverse and a different edge oredges for cleaning during the return traverse are also enjoyed by theembodiment of FIGS. 6 and 7.

Referring to FIG. 8 there is shown an alternative embodiment of thecleaning element 38 in accordance with this invention. In accordancewith the embodiment of FIG. 8 the body 39 of the cleaning element 38includes two slots which serve to define two arms 101 for supporting thebrushes 60 which is adapted to clean the shield 31. By making the outerperiphery 102 of the brushes 60 on the cleaning element 38 larger thanthe inner periphery 61 of the shield 31, the arms 101 serve to act ascantilevers to increase the bias between the brushes and the shield andthereby provide improved cleaning of the shield 31.

Preferably, in accordance with this invention the cleaning element 38,the brushes 60, the carriage 42, the pin 44, the pulleys 54 and 56, andthe cables 51 and 55 are all constructed of non-conductive materialssuch as, for example, nylon, which will not breakdown at the potentialsemployed for corona generation.

While the invention has been described with reference to the use of acorona generator 30 employing a single wire 32, it is equally applicableto a generator employing a plurality of wires by merely providing acorresponding number of slots 40 in the cleaning element 38. For someapplications a double corona generator is employed wherein the shield 31includes two cavities 61 with at least one wire 31 in each of thecavities. It should be apparent that the cleaning apparatus 2 of thisinvention is equally applicable to such a double corona generator orother combination generators. For example, one could merely employ twocleaning elements 38 projecting through two slots 35, one in each of thegenerators with a carriage 42 designed to accept the arms 41 from eachof the respective elements 38. Otherwise, the apparatus would be similarin all respects to that shown. The invention is applicable to coronagenerators in general and is not limited to charging generators.

The term scraping as employed in the present application refers to theremoval of material from the surface of the discharge electrode bystroking with an edged element as described above. The material whichforms the edge should preferably be relatively hard, as for example,have a hardness of about 80 Shore A durometer. The scraping actiondescribed herein is distinguishable from the wiping action of prior artdevices since wiping comprises rubbing with a relatively soft materialrather than stroking with a relatively hard edged element.

The patents, patent applications and texts specifically set forth in thedetailed description are intended to be incorporated'by reference intothe description.

The term electrostatography as employed in the present applicationrefers to the formation and utilization of electrostatic charge patternsfor the purpose of recording and reproducing patterns in viewable form.Electrostatography specifically includes, while not being limited to,electrography wherein an insulating medium is employed to form withoutthe aid of electromagnetic radiation latent electrostatic chargepatterns for producing a viewable record and electrophotography whichemploys a photoresponsive medium to form with the aid of electromagneticradiation, latent electrostatic charge patterns for producing a viewablerecord.

It is apparent that there has been provided in accordance with thisinvention an effective corona generator cleaning apparatus and anelectrostatographic reproducing machine incorporating the same whichfully satisfies the objects, means and advantages set forthhereinbefore. While the invention has been described in conjunction withspecific embodiments therefor, it is evident that may alternatives,modifications and variations will be apparent to those skilled in theart in light of the foregoing description. Accordingly, it is intendedto embrace all such alternatives, modifications and variations as fallwithin the spirit and broad scope of the appended claims.

What is claimed is:

l. A cleaning apparatus for a corona generating device comprising atleast one stationary discharge electrode wire and means for cleaningsaid wire, the improvement wherein said cleaning means comprises: anelement having at least one edge which is operative to deflect andscrape said wire to remove contamination therefrom, means for traversingsaid element in operative engagement along said wire between a homeposition and an end of travel position and means for disengaging saidedge from said wire at said home position.

2. An apparatus as in claim 1 wherein at least one first edge of saidelement engages said at least one electrode wire during traverse in afirst direction and wherein at least one second edge engages saidelectrode wire during traverse of said element in an opposing direction,each of said edges being operative to scrape said electrode wire toremove contaminants therefrom.

3. An apparatus as in claim 1 further including a partially surroundingshield about said electrode wire and means associated with said cleaningmeans for cleaning the interior of said shield.

4. A cleaning apparatus for a corona generating device comprising atleast one stationary discharge electrode wire and means for cleaningsaid wire, the improvement wherein said cleaning means comprises anelement which is operative to deflect and scrape said wire to removecontaminants therefrom, means for traversing said element in operativeengagement with said wire in a first direction and in an opposingdirection, and means for cocking said element in a given direction withrespect to said wire during traverse in said first direction to provideat least one first edge which is operative to engage and scrape said atleast one wire and means for cocking said element in a direction opposedto said given direction during traverse in said opposing direction toprovide at least one second edge which is operative to engage and scrapesaid at least one wire.

5. An apparatus as in claim 4 wherein said element traverses said wirebetween a home position and an end of travel position and wherein saidedges are disengaged from said wire at said home position.

6. An apparatus as in claim 4 wherein said traversing means comprisesmeans for actuating said element to traverse it in said first directionto said end of travel position and means for automatically returningsaid element to said home position when traversing said element in saidopposing direction.

7. An apparatus as in claim 6 wherein said automatic return meanscomprises a spring biased mechanism.

8. An apparatus as in claim 7 further including a partially surroundingshield about said electrode and means associated with said cleaningmeans for cleaning the interior of said shield.

9. An apparatus as in claim 4 wherein said element includes: a bodyportion adapted to be positioned within the interior of said shield, aslot provided in said body portion adapted to receive said wire, legsattached to said body portion on either side of said slot, and wherein aslot is provided in said shield through which said legs can protrude,said apparatus further including a carriage member adapted to pivotablyreceive said legs of said cleaning element, said legs being pivotablyengaged to said carriage and wherein said traversing means drivescarriage in said first direction and in said opposing direction.

10. An apparatus as in claim 9 wherein said traversing means includes afirst cable portion connected between said carriage member and saidreturn means and a second cable portion connected between said carriagemember and said actuating means.

11. An apparatus as in claim 10 wherein said means for returning saidcarriage to said home position comprises a spring biased mechanism.

12. An apparatus as in claim 4 wherein when said element cocks in saidgiven or opposing directions it cocks longitudinally to the axis of saidwire.

13. An apparatus as in claim 4 wherein when said element cocks in saidgiven or opposing directions it cocks traverse to the axis of said wire.

14. An apparatus as in claim 4 wherein when said element cocks in saidgiven or opposing directions it cocks both longitudinally and transverseto the axis of said wire.

15. An apparatus as in claim 3 wherein said means for cleaning saidshield comprises brushes and wherein said brushes comprise a pluralityof loop-type fibers extending outwardly from said cleaning element andoperative to engage the interior of said shield.

16. An apparatus as in claim 9 wherein said cleaning element furtherincludes arms on opposing sides of said slot which are adapted tosupport brushes for cleaning said shield in a cantilever fashion wherebysaid brushes are resiliently engaged against said shield.

'17. In an electrostatographic reproducing apparatus including: anelectrostatic imaging member, means for forming an electrostatic imageon said member, means for developing said electrostatic image, and atleast one corona generating device comprising at least one stationarydischarge electrode wire and means for cleaning said wire, theimprovement wherein said cleaning means comprises: an element having atleast one edge which is operative to deflect and scrape said wire toremove contamination therefrom, means for traversing said element inoperative engagement along said wire between a home position and an endof travel position and means for disengaging said edge from said wire atsaid home position.

18. An apparatus as in claim 17 wherein at least one first edge of saidelement engages said at least one electrode wire during traverse in afirst direction and wherein at least one second edge engages saidelectrode wire during traverse of said element in an opposing direction,each of said edges being operative to scrape said electrode wire toremove contaminants therefrom. v

19. An apparatus as in claim 17 further including a partiallysurrounding shield about said electrode and means associated with saidcleaning means for cleaning the interior of said shield.

20. in an electrostatic reproducing apparatus including: anelectrostatic imaging member, means for forming an electrostatic imageon said member, means for developing said electrostatic image, and atleast one corona generating device comprising at least one dischargeelectrode wire and means for cleaning said discharge electrode, theimprovement wherein said cleaning means comprises: an element which isoperative to deflect and scrape said wire to remove contaminantstherefrom, means for traversing said element in operative engagementwith said wire in a first direction and in an opposing direction andmeans for cocking said element in a given direction with respect to saidwire during traverse in said first direction to provide at least onefirst edge which is operative to engage and scrape said at least onewire and means for cocking said element in a direction opposed to saidgiven direction during traverse in said opposing direction to provide atleast one second edge which is operative to engage and scrape said atleast one wire.

21. An apparatus as in claim 20 wherein said element traverses saidwirebetween a home position and an end of travel position and wherein saidedges are disengaged from said wire at said home position.

22. An apparatus as in claim 20 wherein said traversing means comprisesmeans for actuating said element to traverse it in said first directionto said end of travel position and means for automatically returningsaid element to said home position when traversing said element in saidopposing direction.

23. An apparatus as in claim 22 wherein said automatic return meanscomprises a spring biased mechanism.

24. An apparatus as in claim 20 further including a partiallysurrounding shield about said electrode and means associated with saidcleaning means for cleaning the interior of said shield.

25. An apparatus as in claim 20 wherein when said element cocks in saidgiven or opposing directions it cocks longitudinally to the axis of saidwire.

26. An apparatus as in claim 20 wherein when said element cocks in saidgiven or opposing directions it cocks transverse to the axis of saidwire.

27. An apparatus as in claim 20 wherein when said element cocks in saidgiven or opposing directions it cocks both longitudinally and transverseto the axis of said wire.

28. An apparatus as in claim 1 wherein said traversing means comprisesmeans for actuating said element to traverse it in a first direction tosaid end of travel position and means for automatically returning saidelement to said home position when traversing said element in anopposing direction to said home position.

1. A cleaning apparatus for a corona generating device comprising atleast one stationary discharge electrode wire aNd means for cleaningsaid wire, the improvement wherein said cleaning means comprises: anelement having at least one edge which is operative to deflect andscrape said wire to remove contamination therefrom, means for traversingsaid element in operative engagement along said wire between a homeposition and an end of travel position and means for disengaging saidedge from said wire at said home position.
 2. An apparatus as in claim 1wherein at least one first edge of said element engages said at leastone electrode wire during traverse in a first direction and wherein atleast one second edge engages said electrode wire during traverse ofsaid element in an opposing direction, each of said edges beingoperative to scrape said electrode wire to remove contaminantstherefrom.
 3. An apparatus as in claim 1 further including a partiallysurrounding shield about said electrode wire and means associated withsaid cleaning means for cleaning the interior of said shield.
 4. Acleaning apparatus for a corona generating device comprising at leastone stationary discharge electrode wire and means for cleaning saidwire, the improvement wherein said cleaning means comprises an elementwhich is operative to deflect and scrape said wire to removecontaminants therefrom, means for traversing said element in operativeengagement with said wire in a first direction and in an opposingdirection, and means for cocking said element in a given direction withrespect to said wire during traverse in said first direction to provideat least one first edge which is operative to engage and scrape said atleast one wire and means for cocking said element in a direction opposedto said given direction during traverse in said opposing direction toprovide at least one second edge which is operative to engage and scrapesaid at least one wire.
 5. An apparatus as in claim 4 wherein saidelement traverses said wire between a home position and an end of travelposition and wherein said edges are disengaged from said wire at saidhome position.
 6. An apparatus as in claim 4 wherein said traversingmeans comprises means for actuating said element to traverse it in saidfirst direction to said end of travel position and means forautomatically returning said element to said home position whentraversing said element in said opposing direction.
 7. An apparatus asin claim 6 wherein said automatic return means comprises a spring biasedmechanism.
 8. An apparatus as in claim 7 further including a partiallysurrounding shield about said electrode and means associated with saidcleaning means for cleaning the interior of said shield.
 9. An apparatusas in claim 4 wherein said element includes: a body portion adapted tobe positioned within the interior of said shield, a slot provided insaid body portion adapted to receive said wire, legs attached to saidbody portion on either side of said slot, and wherein a slot is providedin said shield through which said legs can protrude, said apparatusfurther including a carriage member adapted to pivotably receive saidlegs of said cleaning element, said legs being pivotably engaged to saidcarriage and wherein said traversing means drives carriage in said firstdirection and in said opposing direction.
 10. An apparatus as in claim 9wherein said traversing means includes a first cable portion connectedbetween said carriage member and said return means and a second cableportion connected between said carriage member and said actuating means.11. An apparatus as in claim 10 wherein said means for returning saidcarriage to said home position comprises a spring biased mechanism. 12.An apparatus as in claim 4 wherein when said element cocks in said givenor opposing directions it cocks longitudinally to the axis of said wire.13. An apparatus as in claim 4 wherein when said element cocks in saidgiven or opposing directions it cocks traverse to the axis of said wire.14. An apparatus as in claim 4 wherein when said element cocks in saidgiven or opposing directions it cocks both longitudinally and transverseto the axis of said wire.
 15. An apparatus as in claim 3 wherein saidmeans for cleaning said shield comprises brushes and wherein saidbrushes comprise a plurality of loop-type fibers extending outwardlyfrom said cleaning element and operative to engage the interior of saidshield.
 16. An apparatus as in claim 9 wherein said cleaning elementfurther includes arms on opposing sides of said slot which are adaptedto support brushes for cleaning said shield in a cantilever fashionwhereby said brushes are resiliently engaged against said shield.
 17. Inan electrostatographic reproducing apparatus including: an electrostaticimaging member, means for forming an electrostatic image on said member,means for developing said electrostatic image, and at least one coronagenerating device comprising at least one stationary discharge electrodewire and means for cleaning said wire, the improvement wherein saidcleaning means comprises: an element having at least one edge which isoperative to deflect and scrape said wire to remove contaminationtherefrom, means for traversing said element in operative engagementalong said wire between a home position and an end of travel positionand means for disengaging said edge from said wire at said homeposition.
 18. An apparatus as in claim 17 wherein at least one firstedge of said element engages said at least one electrode wire duringtraverse in a first direction and wherein at least one second edgeengages said electrode wire during traverse of said element in anopposing direction, each of said edges being operative to scrape saidelectrode wire to remove contaminants therefrom.
 19. An apparatus as inclaim 17 further including a partially surrounding shield about saidelectrode and means associated with said cleaning means for cleaning theinterior of said shield.
 20. In an electrostatic reproducing apparatusincluding: an electrostatic imaging member, means for forming anelectrostatic image on said member, means for developing saidelectrostatic image, and at least one corona generating devicecomprising at least one discharge electrode wire and means for cleaningsaid discharge electrode, the improvement wherein said cleaning meanscomprises: an element which is operative to deflect and scrape said wireto remove contaminants therefrom, means for traversing said element inoperative engagement with said wire in a first direction and in anopposing direction and means for cocking said element in a givendirection with respect to said wire during traverse in said firstdirection to provide at least one first edge which is operative toengage and scrape said at least one wire and means for cocking saidelement in a direction opposed to said given direction during traversein said opposing direction to provide at least one second edge which isoperative to engage and scrape said at least one wire.
 21. An apparatusas in claim 20 wherein said element traverses said wire between a homeposition and an end of travel position and wherein said edges aredisengaged from said wire at said home position.
 22. An apparatus as inclaim 20 wherein said traversing means comprises means for actuatingsaid element to traverse it in said first direction to said end oftravel position and means for automatically returning said element tosaid home position when traversing said element in said opposingdirection.
 23. An apparatus as in claim 22 wherein said automatic returnmeans comprises a spring biased mechanism.
 24. An apparatus as in claim20 further including a partially surrounding shield about said electrodeand means associated with said cleaning means for cleaning the interiorof said shield.
 25. An apparatus as in claim 20 wherein when saidelement cocks in said given or opposing directions it cockslongitudinally to the axis of said wire.
 26. An apparatus as in claim 20wherein when said element coCks in said given or opposing directions itcocks transverse to the axis of said wire.
 27. An apparatus as in claim20 wherein when said element cocks in said given or opposing directionsit cocks both longitudinally and transverse to the axis of said wire.28. An apparatus as in claim 1 wherein said traversing means comprisesmeans for actuating said element to traverse it in a first direction tosaid end of travel position and means for automatically returning saidelement to said home position when traversing said element in anopposing direction to said home position.